1. Field of the Invention
The present invention relates to a governor for an internal combustion engine, and more particularly to a hydraulic-controlled electronic governor employed in a fuel injection system for a Diesel engine.
2. Description of the Prior Art
Hitherto, in this type of the governor, a Bosch-type governor shown in FIG. 1 of the accompanying drawings is well known. In the Bosch-type governor, as shown in FIG. 1, a solenoid valve 1 is controlled to be turned on or off by a controller C, to cause a valve spool 2 to be operated, whereby a hydraulic pressure fed to a power piston/cylinder unit 3 is controlled. The thus controlled hydraulic pressure moves a control rack 4 to a position in which a resilient force of a return spring 5 balances a hydraulic force acting on a piston 3a of the power piston/cylinder unit 3. A rack position detecting sensor 6 detects such movement of the control rack 4 to issue a detecting signal to the controller C so as to constitute a feedback control for controlling the position of the control rack 4.
Incidentally, in addition to such detecting signal issued from the rack position detecting sensor 6, the controller C receives also other sensor's signals as to an inclination angle of an accelerator lever (not shown), an engine speed and the like. The reference numeral 7 denotes a gear pump which serves as a hydraulic pressure source.
In the above-mentioned conventional governor, in controlling a position of the control rack 4 for controlling an amount of fuel injection according to traveling conditions of a vehicle and loading conditions of the same, the rack position detecting sensor 6 constitutes an indispensable component of the governor, so that the governor does not function when some malfunction occurs in the sensor 6 itself or in a detecting signal transmitting path between the sensor 6 and the controller C.